Kiisortoqia soperi
| Kiisortoqia soperi | ||||||||
|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||
| lower Cambrian | ||||||||
| 521 to 514 million years | ||||||||
| Locations | ||||||||
| Systematics | ||||||||
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| Scientific name of the genus | ||||||||
| Kiisortoqia | ||||||||
| Stein , 2010 | ||||||||
| Scientific name of the species | ||||||||
| Kiisortoqia soperi | ||||||||
| Stein , 2010 | ||||||||
Kiisortoqia soperi is an extinct species of arthropod from the early Cambrian of the Sirius Passet faunal community . The large antennae are very similar to those of the Anomalocaridida .
features
The body of Kiisortoqia soperi consisted of a simple head shield, 16 trunk segments ( tergites ) and a tail shield . The species reached a length of 234 to 534 mm and was approximately elliptical in its external appearance, about twice as long as wide, with the widest point in the front third of the body at the 3rd to 5th tergite.
The head shield was simple, convex in shape, wider than it was long, and made up about 20% of the total body length. The tergites were short, about five times as wide as they were long, and the trailing edge of each tergite overlaid the next by about a fifth of its length. Tergites 1 to 5 were all about the same width, the following tergites became narrower and narrower towards the rear. In the middle an axis was clearly visible, which was about half the width of a tergite and gave it a three-lobed shape. At the lateral ends of each tergite there were spines that became longer towards the rear. The small tail shield was semicircular, about half as long as it was wide and the front half up to two thirds of the tail shield also had a three-lobed shape.
At the head shield sat ventral a pair of large limbs, the so-called antennule which were about one-half to two-thirds as long as the body. They consisted of a stem and about 15 cylindrical links, the stem being twice as long as the following links. The limbs had a flat outside and two widely spaced spines towards the middle.
The other limbs, three pairs on the head shield and 16 more on each trunk segment, consisted of two branches (constructed like a split leg in crustaceans ) and increased in size up to the 5th tergite and then became smaller again. The basipodit was long, trapezoidal and had two rows with different numbers of thorns. The endopodit consisted of nine cylindrical podites. The eighth podit had two side spikes that flanked the ninth long podit. The exopodite was a paddle-like rag, which was fringed with bristles. The length was a little more than two thirds of the length of the endopodit.
Way of life
An exact way of life cannot be determined due to the lack of direct evidence, but conclusions can be drawn based on the morphology .
It is believed that Kiisortoqia soperi was a predatory swimmer. The large paddle-like exopodites were believed to be suitable for swimming. With the robust antennae, K. soperi was probably able to grasp its prey and with the spiky basipodites it could grab its prey and bring it to its mouth.
etymology
The name of the genus is derived from the Greenlandic word kiisortoq for predator or hunter. The specific epithet was chosen in honor of Norman John ("Jack") Soper, who together with AK Higgins, the discoverer of the Sirius Passet Fauna Community , collected the first fossils there.
Locations
More than 170 specimens of the species were found during various expeditions between 1985 and 2006 in the Sirius-Passet lower- Cambrian conservation deposit on Pearyland in northern Greenland . Most of the specimens have been more or less completely preserved, splintered fossils have not been discovered.
Systematic position
Kiisortoqia soperi fulfills three basic properties of the arthropod in the strict sense ( Euarthropoda ): a head shield with antennae or antennae and three pairs of other extremities, post-antennular two-branched limbs and an exopodite fringed with bristles. An exact position within the arthropod cannot be determined due to the possible lack of eyes and the shape of the tail shield. A possible synapomorphism of the antennae with the jaw-claw carriers (Chelicerata) is purely speculative.
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literature
- Martin Stein : A new arthropod from the Early Cambrian of North Greenland, with a 'great appendage'-like antennula . Zoological Journal of the Linnean Society 158 (3), 2010: 477-500. PDF
Individual evidence
- ↑ D. Waloszek, A. Maas, Chen J., M. Stein: Evolution of cephalic feeding structures and the phylogeny of Arthropoda . Palaeogeography, Palaeoclimatology, Palaeoecology 254, 2007: 273-287.
- ↑ Chen J., D. Waloszek, A. Maas: A new 'greatappendage' arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial anteroventral appendages . Lethaia 37, 2004: 3-20.